Synonyms and related words :
baseless, controvertible, empty, groundless, idle, ill-founded, insupportable, intolerable, unattestable, unbased, unbearable, unconfirmable, undemonstrable, undemonstratable, unendurable, unfounded, ungrounded, unprovable, unsubstantiatable, unsupported, unsustainable, unsustained, untenable, unverifiable, unwarranted, vain, without basis, without foundation